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Two different 2-digit numbers are randomly chosen and multiplied together. What is the probability that the resulting product is even?

 Aug 11, 2018
 #1
avatar+100519 
+1

There are 90  2 digit  numbers.....the total possible pairs   = C(90,2)

 

An odd can only occur if we multiply  any two odds together.....the number of possible pairs  = C(45,2)

 

So....the probability  of an even product  is......  

 

1  - probability of an odd product  =

 

1  - C(45,2)/C(90,2)  =

 

67/89 ≈ 75.3%

 

EDIT to correct a silly error pointed out by Guest...!!!!

 

 

cool cool cool

 Aug 11, 2018
edited by CPhill  Aug 11, 2018
edited by CPhill  Aug 11, 2018
edited by CPhill  Aug 11, 2018
 #2
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CPhill: Don't you have only: 99 - 10 + 1 =90 - 2-digit numbers??

 Aug 11, 2018
 #3
avatar+100519 
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Yep...my bad...see edit....

 

 

cool cool cool

CPhill  Aug 11, 2018

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